NDB-Series - ABB Semiconductors

Specification sheet Deltapi N Series

Pneumatic Transmitters

Model NDB

Gauge pressure transmitter

The blind type pressure transmitter, mod. NDB, is used to

measure a pressure and convert it into a proportional

pneumatic signal.

The instrument works on the force-balance principle and

consists of two main units:

the measuring unit comprises a main body which houses a

bellows unit, clamped in the main body forging by means of a

flange. The bellows unit releves the pressure applied to the

positive connection port. The negative connection port is open

to atmosphere. The bellows unit can withstand the maximum

overrange on positive side without damage.

the transmission unit converts the differential force applied to

the measuring element into a proportional output pneumatic

signal.

The output pressure, generated by a flapper nozzle relay, is fed

to a feedback bellows with a rising pressure until the bellows

force balances that of the measuring element.

Span value continuously adjustable by an internal micrometric

screw.

Zero value adjustable by an external screw.

Mounting in a vertical position on 2in diameter pipe by a

special bracket.

OPTIONAL EXTRA FEATURES

A zero elevation or suppression device allows to set as a

zero of the transmitter a measured variable value different from

zero.

The sum of the zero suppression value (S) plus the calibrated

span cannot exceed the upper range limit (M) suitable by the

bellows capsule : S + span ≤ M (see table).

GENERAL CHARACTERISTICS

Air filter regulator can be directly mounted on the transmitter,

with or without pressure gauge, and connected with piping and

fittings either in stainless steel or copper.

Special versions of air filter regulator and gauges, in stainless

steel, are available on request.

Oxygen measurements a special degreasing and final test

operations can be required on the oxygen measuring

transmitter.

Body and flange material

Carbon steel, AISI 316L, Monel

Body bolts and nuts material

high tensile carbon steel;

AISI 316 Class A4-70 per ISO 3506;

high tensile stainless steel, in compliance with

NACE MR0175

Measuring bellows material

AISI 316L, Monel

Gaskets material

PTFE, Viton

Cover material

thermoplastic resin

Surface protections

- carbon steel body and flange: zinc plating and chrome

passivation

- AISI 316L body and flange: no protection

Process connections (see figure ref. D )

1/2 in NPT-F

Pneumatic connections

- Air supply (in figure ref. A): 1/4 in NPT-F

- Output (in figure ref. B): 1/4 in NPT-F

Pressure gauge

Brass with stainless steel case (all stainless steel on request)

external diameter 51 mm; 0-200 kPa, 0-2 bar and 0-30 psi

indication on 82 mm/260° scale.

Air filter regulator

with copper or stainless steel piping, as specified.

Die cast aluminium alloy with light grey epoxy finish.

Net weight (maximum)

7 kg approx

Packing

expanded polythene box

Air supply

nom. 140 kPa (1.4 bar, 20 psi); min. 125 kPa (1.25 bar,

18 psi); max. 175 kPa (1.75 bar, 25 psi)

Output signal

20 to 100 kPa/0.2 to 1 bar, 3 to 15 psi or 0.2 to 1 kg/cm2

Static air consumption

350 Nl/h

Maximum output flow

- with rising output pressure: 30 Nl/min.

- with falling output pressure: 40 Nl/min.

Accuracy

± 0.5% F.S.D. (typical)

Thermal drift (for ambient temperature variation between

-20°C and +65°C)

Bellows A

- span 1.7 to 3.4: 0.6% / 10°C

- span 3.4 to 17: 0.3% / 10°C

Bellows B

- span 3.5 to 7: 0.6% / 10°C

- span 7 to 35: 0.3% / 10°C

Bellows C

- span 7 to 14: 0.8% / 10°C

- span 14 to 70: 0.4% / 10°C

Bellows D

- span 14 to 28: 1% / 10°C

- span 28 to 140: 0.5% / 10°C

Pressure effect for variation of :

- Bellows A - 1.75 MPa (17.5 bar): 0.25%

- Bellows B - 3.5 MPa (35 bar): 0.25%

- Bellows C - 5 MPa (50 bar): 0.3%

- Bellows D - 5 MPa (50 bar): 0.3%

Degree of protection in accordance with IEC 529

IP55

Ambient temperature limits

-40 and + 120°C

OVERRANGE

LIMIT

3.5 MPa

35 bar

7 MPa

70 bar

14 MPa

140 bar

28 MPa

280 bar

MAXIMUM

ZERO

ELEVATION

100 kPa

1 bar

100 kPa

1 bar

100 kPa

1 bar

100 kPa

1 bar

MAXIMUM

ZERO

SUPPRESSION (S)

RANGE

LIMITS

lower and upper (M)

SPAN LIMITS

min. and max.

170 and 1700 kPa

1.7 and 17 bar

350 and 3500 kPa

3.5 and 35 bar

700 and 7000 kPa

7 and 70 bar

1400 and 14000 kPa

14 and 140 bar

MEASURING

BELLOWS

2330 kPa

23.3 bar

4650 kPa

46.5 bar

9300 kPa

93 bar

18600 kPa

186 bar

- 100 and 2500 kPa

- 1 and 25 bar

- 100 and 5000 kPa

- 1 and 50 bar

- 100 and 10000 kPa

- 1 and 100 bar

- 100 and 20000 kPa

- 1 and 200 bar

SPECIFICATIONS

The data were obtained from laboratory tests on standard instruments with:

carbon steel or AISI 316L body and flange; AISI 316L bellows unit; gasket: Viton;

calibration span: 800 kPa - 8 bar (bellows A), 1700 kPa - 17 bar (bellows B), 3500 kPa - 35 bar (bellows C),

7000 kPa - 70 bar (bellows D).

de VERSION

Standard with body bolts and nuts in high tensile carbon steel

Standard with body bolts and nuts in AISI 316

Standard with body bolts and nuts in high tensile stainless steel

fg BODY AND FLANGE (*)

Carbon steel / Carbon steel

Carbon steel / AISI 316L

AISI 316L / AISI 316L

AISI 316L / Monel

(*) Only the flange is in contact with fluid

Note 1: Multiply by 10 the value in kPa (MPa) to obtain mbar (bar).

(*) Suitable for oxygen service

MEASURING ELEMENT

Bellows material Range limits - 0 and

kPa psi Span limits

kPa (psi) - (Note 1)

170 and 1700 (24.6 and 246)

350 and 3500 (50.7 and 507)

700 and 7000 (101.5 and 1015)

1400 and 14000 (203 and 2030)

170 and 1700 (24.6 and 246)

350 and 3500 (50.7 and 507)

2500

5000

10000

20000

2500

5000

362

725

1450

2900

362

725

AISI 316L

Monel

AISI 316L (*)

ORDERING INFORMATION

Select one character or set of characters from each category and specify complete catalog number.

abc de fg hi j k lm

BASE MODEL

VERSION

BODY AND FLANGE

MEASURING ELEMENT

GASKETS

OUTPUT

EXTRAS

PRODUCT CODE

abc BASE MODEL

Gauge pressure transmitter

Code

NDB

GASKETS

(*) Suitable for oxygen service

(**) Not in contact with process fluid

Fulcrum diaphragm gasket (**)

Viton

PTFE

jViton

PTFE (*)

Measuring element gasket

OUTPUT 1

3 to 15 psi

3 to 15 psi with zero elevation device

3 to 15 psi with zero suppression device

0.2 to 1.0 kg/cm2

0.2 to 1.0 kg/cm2 with zero elevation device

0.2 to 1.0 kg/cm2 with zero suppression device

20 to 100 kPa / 0.2 to 1 bar

20 to 100 kPa / 0.2 to 1 bar with zero elevation device

20 to 100 kPa / 0.2 to 1 bar with zero suppression device

According to

ANSI/ISA S 51.1-1979

standard terminology

Piping

material Air filter

regulator Pressure

gauge

EXTRAS

- -

with

- -

with

Identification

tag material

Stainless Steel

- -

Stainless Steel

Copper

Stainless Steel

Copper

Compliance to NACE class II bolting, according to specification MR0175, latest revision

The Company's policy is one of continuous product

improvement and the right is reserved to modify the

specifications contained herein without notice.

SS/NDB Rev 7

MOUNTING DIMENSIONS

ABB Inc.

125 East County Line Road

Warminster, Pa 18974

USA

Tel. (215) 674-6000

Facsimile (215) 674-7183

ABB Ltd.

Howard Road

St. Neots, Cambs.

England PE19 8EU

Tel. (01480) 475321

Facsimile (01480) 217948

ABB Instrumentation spa

Via Statale, 113

22016 Lenno (CO)

Italia

Tel. 0344 58111

Facsimile 0344 56278